Ammonia Engine Pre-Chamber Ignition Acceleration
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Solution Overview
Problem
Ammonia combustion engines face challenges with slow burning speed, combustion stability issues, and increased nitrogen oxide formation due to the slow laminar flame speed of ammonia, which limits their efficiency and ability to operate under lean conditions.
Innovation Solution
Incorporating a pre-chamber with a spark plug and fluidic connection via nozzles to initiate ignition in the pre-chamber, accelerating the ignited gas mixture into the main chamber, allowing for simultaneous ignition at multiple points and reducing the required ammonia amount, while optionally using a secondary fuel injector to enhance combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ammonia is used as fuel in combustion engine, then carbon emissions and sulfur emissions are eliminated, but burning speed is slow and combustion stability deteriorates
Solution Approach 1:
The combustion chamber is divided into a pre-chamber and a main chamber. The pre-chamber serves as a separate ignition zone where ammonia combustion is initiated, and the ignited gas mixture is then injected into the main chamber to propagate combustion. This segmentation allows the combustion process to start in a controlled environment and then spread efficiently to the main fuel charge, resolving the contradiction between using ammonia as a clean fuel and achieving adequate burning speed.
Solution Approach 2:
Combustion is initiated in advance in the pre-chamber before the main chamber combustion proceeds. The spark plug ignites the ammonia-air mixture in the pre-chamber first, creating an ignited gas mixture that is then injected into the main chamber to trigger rapid combustion of the remaining ammonia. This preliminary ignition action overcomes ammonia's slow burning characteristics by providing a head start to the combustion process.
2Object-affected harmful factors
If ammonia combustion is used, then carbon emissions are reduced, but combustion stability deteriorates due to slow flame speed
Solution Approach 1:
By separating the ignition process into a distinct pre-chamber, the combustion stability is improved. The pre-chamber provides a stable environment for initial ignition, and the injected ignited gas mixture ensures consistent combustion propagation into the main chamber. This segmentation decouples the ignition stability requirement from the main combustion process, allowing reliable operation while maintaining ammonia's zero carbon emission benefit.
Solution Approach 2:
The pre-chamber acts as an intermediary between the spark plug ignition source and the main ammonia fuel charge. It conditions the gas mixture and generates an ignited plasma that serves as a stable ignition source for the main chamber, thereby improving combustion stability without compromising the carbon-free combustion advantage of ammonia.
3Device complexity
If conventional ignition is used in main chamber, then structure is simple, but combustion acceleration is insufficient and thermal efficiency decreases
Solution Approach 1:
The ignition system is segmented into a pre-chamber and main chamber with a fluidic connection. This segmentation enables combustion acceleration through the injection of ignited gas mixture from the pre-chamber into the main chamber, significantly improving thermal efficiency. The additional structural element (pre-chamber) is justified by the substantial gain in combustion performance and energy efficiency.
Solution Approach 2:
The pre-chamber performs preliminary combustion preparation by igniting a portion of the ammonia-air mixture before injecting the ignited gas into the main chamber. This preliminary action accelerates the overall combustion process, allowing the engine to achieve higher thermal efficiency and power output, which compensates for the increased structural complexity.
4Object-affected harmful factors
If ammonia is combusted, then sulfur emissions are eliminated, but nitrogen oxide formation increases under lean conditions which cannot be avoided
Solution Approach 1:
The pre-chamber enables preliminary combustion of a portion of the ammonia fuel before the main chamber combustion. This staged combustion approach allows for better control of combustion conditions, including the ability to operate with leaner ammonia-air mixtures in the main chamber while maintaining stable combustion through the pre-chamber ignition source, thereby reducing nitrogen oxide formation while preserving sulfur emission elimination.
5Speed
If pre-chamber is added for combustion acceleration, then burning speed increases and thermal efficiency improves, but device complexity increases
Solution Approach 1:
The combustion chamber is segmented into pre-chamber and main chamber with a fluidic connection. This segmentation achieves rapid combustion acceleration through the injection mechanism while maintaining a relatively simple overall structure. The pre-chamber can be integrated into the existing cylinder head architecture, minimizing the increase in device complexity while delivering significant burning speed improvements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution accelerates combustion, reduces ammonia usage, and decreases nitrogen oxide formation, improving thermal efficiency and stability, enabling operation under lean conditions.
Implementation Method 1
a spark plug for igniting the ammonia in the main chamber according to the generic term of claim 1
Implementation Method 2
the at least one nozzle being configured to accelerate the ignited gas mixture from the pre-chamber into the main chamber after ignition of the gas mixture in the pre-chamber
Implementation Method 3
a main chamber for combustion of the ammonia
Data Source
Figure 1~2
AI summary
The invention relates to an ammonia-burning combustion engine (1) with a main chamber (5) and a spark plug (10). A pre-chamber (11) with at least one nozzle (12) is arranged between the main chamber (5) and the spark plug (10). The spark plug (10) is arranged in the pre-chamber (11) and the at least one nozzle (12) fluidically connects the main chamber (5) and the pre-chamber (11).